diff --git a/pkgs/top-level/emacs-packages.nix b/pkgs/top-level/emacs-packages.nix
index 781a6b10bf69..8dac3fa52df3 100644
--- a/pkgs/top-level/emacs-packages.nix
+++ b/pkgs/top-level/emacs-packages.nix
@@ -710,6 +710,22 @@ let self = _self // overrides;
     meta = { licence = gpl3Plus; };
   };
 
+  smex = melpaBuild rec {
+    pname = "smex";
+    version = "20141210";
+    src = fetchFromGitHub {
+      owner  = "nonsequitur";
+      repo   = pname;
+      rev    = "aff8d4485139ac28f1c7e62912c0d0d480995831";
+      sha256 = "0017f1ji7rxad2n49dhn5g0pmw6lmw80cqk6dynszizj46xpbqfp";
+    };
+    meta = {
+      description = "M-x enhancement for Emacs build on top of Ido";
+      homepage = https://github.com/nonsequitur/smex/;
+      license = emacs.meta.license; # should be "same as Emacs"
+    };
+  };
+
   structured-haskell-mode = melpaBuild rec {
     pname = "shm";
     version = external.structured-haskell-mode.version;